A magnetic field sensitive MOSFET (usually referred to as MagFET) is a magnetic field sensor, which makes use of the deflection of the current passing through the MOS channel of a MagFET caused by a magnetic field. This deflection is caused by the Lorentz force acting on the charge carriers in the MOS channel. In so-called split-drain MagFETs a source current of the MagFET is split into two drain currents, wherein the ratio between the drain currents depends on the external magnetic field. In other MagFET designs a voltage drop along a transverse direction with respect to the direction of the current flow through the MOS channel can be tapped. The magnitude of the voltage drop depends on the Lorentz force acting on the charge carriers (electrons in case of an n-channel MagFET) and thus the voltage drop can be evaluated to measure the magnetic field.
There is a general need for magnetic field sensors including MagFETs and suitable sensor circuit for controlling the operation of the sensor and processing the sensor signal.